<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Title</title>
</head>
<body>
<div id="app">
    <h2 v-once>
        {{message}}
    </h2>
    <h3>
        <span>数字：{{counter}}</span>
    </h3>
    <h1>{{message}}</h1>
    <button v-on:click="changeMessage">改变message</button>
</div>
<script src="https://unpkg.com/vue@3"></script>
<script>
    const app=Vue.createApp({
        data(){
            return{
                message:"Hello Vue",
                counter:100
            }
        },
        methods:{
            changeMessage:function(){
                this.message="你好啊，李银河！"
                this.counter+=100
            }
        }
    })

    app.mount("#app")
</script>
</body>
</html>